A basic need in some image capturing applications is to track a predetermined object or area. Unlike audio tracking, in which the acquisition of a signal is performed omni-directionally, visual tracking may require changing the capturing direction or other parameters due to movement of the capturing device, the viewed object or area, or both. In such situations, there may exist a dilemma whether to capture only the object or area and a small surrounding region, or to capture a larger area. Capturing only a small surrounding enables relatively high resolution, and obtaining fine details about the target object or area. However, if the object of the capturing device moved, the object may disappear from the image, which will necessitate zooming out, locating the object and zooming back in. However, capturing the larger environment enables the viewer to keep the large picture and be able to track the moving object or area, but in much less detail, which may harm the tracking objective.
In still images acquisition, it is possible to use a large sensor, comprising many sensor cells, and to capture a large area in fine detail. However, in video imaging, wherein multiple images should be processed every second, processing the values obtained by a large number of sensor cells poses a problem. Thus in current video imaging systems, a choice should be made between a large area captured with low resolution, and smaller area captured with high resolution. A possible solution to this dilemma is to present two or more images, arranged in any required way, wherein one or more images show the area of interest in the required resolution, and one or more other images show areas neighboring to or including the area of interest, in preferably lower resolutions. However, this solution does not provide easy navigation and orientation of a user, since the user has to integrate in his or her mind the information from multiple images.
Yet another solution is presenting a panoramic image over a widescreen display. Such presentation does not necessarily provide more details to a required area, is specifically limited to wide captured scenes, and distorts the whole image, thus limiting orientation.
Thus there is a need in the art for a method and apparatus for enabling capturing of relatively large areas while providing high resolution for a particular area of the captured scene. The method and apparatus should be appropriate for video capturing, and enable tracking of objects or areas which are moving relatively to the capturing device.